A232224 - cp's OEIS frontend

A232224 Number of ways of arranging n chords on a circle (handshakes between 2n people across a table) with exactly 3 simple intersections.

n	a(n)
0	0
1	0
2	0
3	1
4	20
5	195
6	1430
7	9009
8	51688
9	278460
10	1434120
11	7141530
12	34648856
13	164663785
14	769491450
15	3546222225
16	16152872400
17	72846725160
18	325722299760
19	1445598337950
20	6373942543800
21	27942072562950
22	121863923024844
23	529043313674106
24	2287209524819120

[0, 0, 0, 1, 20, 195, 1430, 9009, 51688, 278460, 1434120, 7141530, 34648856, 164663785, 769491450, 3546222225, 16152872400, 72846725160, 325722299760, 1445598337950, 6373942543800, 27942072562950, 121863923024844, 529043313674106, 2287209524819120]

cp's OEIS Frontend

A232224 Number of ways of arranging n chords on a circle (handshakes between 2n people across a table) with exactly 3 simple intersections.

Table of values

List of values